
/* Copyright  2009
   @Author
   Richard Changde Yin            e-mail yinchangde@hotmail.com

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */





#include <server_includes.h>
#include <natural_join_column.h>
#include <table_list.h>
#include <session.h>

Natural_join_column::Natural_join_column(Field *field_param,
                                         TableList *tab)
{
  assert(tab->table == field_param->table);
  table_field       = field_param;
  table_ref         = tab;
  is_common         = false;
}


const char *Natural_join_column::name()
{
  return table_field->field_name;
}


Item *Natural_join_column::create_item(Session *session)
{
  return new Item_field(session,
                        &session->lex->current_select->context,
                        table_field);
}


Field *Natural_join_column::field()
{
  return table_field;
}


const char *Natural_join_column::table_name()
{
  assert(table_ref);
  return table_ref->alias;
}


const char *Natural_join_column::db_name()
{
  /*
    Test that TableList::db is the same as TABLE_SHARE::db to
    ensure consistency. An exception are I_S schema tables, which
    are inconsistent in this respect.
  */
  assert(!strcmp(table_ref->db,table_ref->table->s->db.str) ||
              (table_ref->schema_table && table_ref->table->s->db.str[0] == 0));

  return table_ref->db;
}
